Patent Document 1 discloses a controller for an AC electric motor that applies voltage from a DC power supply to a multi-phase AC electric motor by means of a plurality of power converters. The controller comprises: detecting means for detecting an output current from the power converters; first coordinate transforming means for transforming a current detection value from one of the power converters into coordinates on a rotating coordinate system; second coordinate transforming means for transforming a current detection value from the other power converter into coordinates on the rotating coordinate system; average value calculating means for calculating an average output current value based on output signals from the first and second coordinate transforming means; voltage command generating means for generating a representative two-phase voltage command value based on an output from the average value calculating means, an excitation current command value, and a torque current command value; correction signal generating means for generating a correction signal based on outputs from the first and second coordinate transforming means; voltage command correcting means for generating a plurality of two-phase voltage command values based on an output from the correction signal generating means and an output from the voltage command generating means; and a plurality of command coordinate transforming means for generating a three-phase voltage command based on an output from the voltage command correcting means, wherein an unbalanced current of the multi-phase AC electric motor is reduced.